Without limiting the scope of the invention, its background is described in connection with projectiles made by injection molding for use in ammunition. Conventional ammunition projectiles for rifles and machine guns, as well as larger caliber weapons, are made from brass or lead that are machined, cast, molded or coated.
For example, U.S. Patent Application Publication No. 2003/0101891 entitled, “Jacketed bullet and methods of making the same” discloses a jacketed firearms projectile having a jacket thickness less than approximately 0.025 inches thick are described, where the density of the projectile core has been selected so that the jacketed projectile has a weight that is at least substantially the same as a reference firearms projectile, such as a lead projectile, having substantially the same size and shape. In one aspect, the projectile is a frangible projectile. In another aspect, the projectile is lead-free. In yet another aspect, the projectile is incorporated in a cartridge. Methods for forming the projectile and forming cartridges containing the projectiles are also disclosed.
U.S. Patent Application Publication No. 2009/0042057 entitled, “Metal composite article and method of manufacturing” discloses a composite metal article includes a higher melting point metal, a lower melting point alloy and at least one other metal with an intermediate melting point between that of the higher melting point metal and the lower melting point alloy. The at least one other metal is selected to aid in sinter-densification of the higher melting point metal in a temperature range above the liquid temperature of the lower melting point alloy and below the melting point of the at least one other metal.
U.S. Pat. No. 7,204,191 entitled, “Lead free, composite polymer based bullet and method of manufacturing” discloses a lead-free, composite polymer based bullet and cartridge case and methods of manufacturing the same, wherein the composite polymer material includes a tungsten metal powder, nylon 6/6, nylon 6, short glass fibers, as well as additives and stabilizers. The cartridge case includes a lip lock configured to matingly engage a cannelure formed along an outer circumferential surface of the bullet.
U.S. Pat. No. 7,392,746 entitled, “Bullet composition” discloses a lead free environmentally friendly ammunition which may be tailored within a range of compositions for specific uses, but generally comprises a mixture of metal powder and mineral filler in combination with a water soluble binder plastic resin and a lubricant. For hunting uses and other uses requiring high level accuracy the amount of metal powder is increased, for other uses where precision shooting is less important such as drug dosing of animals, less metal is used along with increased amounts of mineral filler. The bullets are accurate, and can be frangible.
Shortcomings of the known methods of producing projectiles for ammunition include the limitation of materials that can be used to form projectiles and the lengthy time for manufacturing.